---
title: Plugin: Thelio IO
---

## Introduction

This plugin is used to detach the Thelio IO device to DFU mode.

To switch to this mode `1` has to be written to the `bootloader` file
in sysfs.

## GUID Generation

These devices use the standard USB DeviceInstanceId values, e.g.

* `USB\VID_1209&PID_1776&REV_0001`

## Update Behavior

The device usually presents in runtime mode, but on detach re-enumerates with a
different USB VID and PID in DFU mode. The device is then handled by the `dfu`
plugin.

On DFU attach the device again re-enumerates back to the runtime mode.

For this reason the `REPLUG_MATCH_GUID` internal device flag is used so that
the bootloader and runtime modes are treated as the same device.

## Vendor ID Security

The vendor ID is set from the USB vendor, in this instance set to `USB:0x1209`

## External Interface Access

This plugin requires read/write access to `/dev/bus/usb`.

## Version Considerations

This plugin has been available since fwupd version `1.3.2`.

## Owners

Anyone can submit a pull request to modify this plugin, but the following people should be
consulted before making major or functional changes:

* Jeremy Soller: @jackpot51
